WateringTimesWatering plan, $19
Cotinus coggygria ssp. & cvs., WUCOLS IV

How often to water smoke tree in California

In July in the Central Valley, established smoke tree in loam needs a deep watering about every 20 days: about 55 gallons each time under a 10 foot canopy, about 19 gallons a week. Smoke tree is a deciduous shrub or small tree whose faded flower clusters turn into billowing plumes of pink to purple hairs. Purple-leaved forms such as 'Royal Purple' are popular, and the leaves color brightly in fall. Once established it is drought tolerant, and it wants full sun and well drained soil.

ShrubTreeRated for 5 of 6 zones

How often to water smoke tree, month by month

Your city
Canopy width
10 ft
Your soil

Type your city above and the days between waterings and the gallons appear here, worked out from your city's climate table. Or read the figures by climate zone further down.

Every month, on your water days. The personal plan prints this for smoke tree and the rest of your yard, on the days your water supplier allows.Get the plan for $19

How this is worked out: established roots fill the top 1.5 feet of soil, and you water again when that soil has dried halfway. Loam soil holds about 1.5 inches of water per foot. Water the whole area under the branches, and skip a watering after a good soaking rain.

Which soil do you have?

Dig down a few inches, take a handful of moist soil and squeeze it.

  • Sandy: gritty, falls apart when you open your hand, will not form a ball.
  • Loam: forms a soft ball that crumbles when you poke it.
  • Clay: forms a firm, sticky ball and squeezes out into a ribbon between thumb and finger.

Still not sure? Pick loam. Most garden beds sit between sand and clay.

How to measure canopy width

A tree with its canopy width marked across the widest branches and the circle under it shaded blue

Measure across the branches, from the tips of the outer leaves on one side to the tips on the other. A tape works, or pace it out.

Water the whole circle under the branches, shown in blue. The gallons here cover that circle.

A wider canopy means more gallons each watering, not more waterings. While the tree is young, measure again each spring.

How to tell it needs water

  • Dig beside a young smoke tree's root ball, and dry soil at 3 to 4 inches means it is time for a soak
  • Leaves drooping through a hot afternoon and into the evening, over dry soil, point to a thirsty young plant
  • A branch or one side wilting and dying while the soil is moist can mean verticillium wilt, a known smoke tree problem
  • Purple leaves turning green on a plant in shade come from too little light, not from the watering
  • Yellowing leaves and dieback over soggy, poorly drained soil point to root stress from too much water

How to water it

  • Water a young smoke tree deeply at the root ball and just beyond, then taper off once it is established
  • Let the soil dry well down between soakings, since established plants tolerate drought
  • Plant in full sun in well drained soil of almost any pH, avoiding low, wet spots
  • Keep it apart from frequently watered lawns and beds that hold the soil moist
  • Shift drip emitters toward the outer branches as the plant spreads

Through the seasons

Water a new smoke tree regularly through its first summer, then let it rely on deep, occasional soakings. Small flowers open in spring, and the faded clusters become smoky plumes through summer. Leaves turn yellow, orange, red or purple in fall before dropping. Winter rain usually covers the dormant months on the coast and in the valley. Low water is its WUCOLS rating in the high desert, South Inland, the Central Valley, the south coast and the north-central coast. WUCOLS marks it as not suited to the low desert.

In pots

Smoke tree has fibrous roots that transplant easily, so a young plant can spend a few years in a large container. Use a free-draining mix. During summer heat, feel the mix every couple of days and water once the top 2 inches are dry. Let the water run through until it drains, then pour off the saucer. A purple-leaved form needs full sun in a pot too, or it fades toward green. In winter the bare shrub needs only occasional water.

1 Your climate zone six WUCOLS zones, each from its own reference city
1.07gal per sq ft in JulyLow water use in the Central Valley zone
A year
6.84 gal per sq ft
Reference
Sacramento climate table
Counts
Plant need, before sprinkler losses
0.300.610.921.20.16JAN0.26FEB0.43MAR0.61APR0.83MAY0.99JUN1.07JUL0.95AUG0.72SEP0.47OCT0.22NOV0.14DEC0.300.610.921.20.16JFM0.61AMJ1.07JAS0.47OND
Gallons per square foot per month, Central Valley. Peak 1.07 in Jul, 6.84 a year.

Monthly water need by climate zone

Smoke Tree: gallons per square foot per month, by WUCOLS climate zone

MonthN. CoastC. ValleyS. CoastS. InlandHi DesertLo Desert
Jan0.150.160.310.310.3–
Feb0.210.260.320.350.37–
Mar0.350.430.460.520.58–
Apr0.470.610.560.640.76–
May0.580.830.640.780.95–
Jun0.640.990.690.921.14–
Jul0.641.070.7911.22–
Aug0.60.950.740.931.12–
Sep0.50.720.60.740.86–
Oct0.350.470.460.530.58–
Nov0.190.220.330.360.37–
Dec0.120.140.260.270.26–
Year4.86.846.27.378.51–

How this is worked out: the WUCOLS water rating for each zone times that zone’s climate for the month. A dash means WUCOLS does not rate the plant there. The figures are what the plant uses, before sprinkler losses.

Plants with the same water needs 16

Rated low water in the Central Valley, like smoke tree. Plants that drink alike can share one valve and one schedule.

LavenderLavandula spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRosemaryRosmarinus officinalislow water, Central Valley1.07 gal/sq ft in JulyBougainvilleaBougainvillea & spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyOlive TreesOlea europaea ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyFig TreesFicus carica ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyCrape MyrtleLagerstroemia spp., hybrids & cvs.low water, Central Valley1.07 gal/sq ft in JulyLantanaLantana camara ssp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySalviaSalvia greggii ssp., cvs. & hybridslow water, Central Valley1.07 gal/sq ft in JulyAloeAloe spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySucculentsEcheveria spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyPomegranate TreesPunica granatumlow water, Central Valley1.07 gal/sq ft in JulyEucalyptusEucalyptus polyanthemoslow water, Central Valley1.07 gal/sq ft in JulyPine TreesPinus canariensislow water, Central Valley1.07 gal/sq ft in JulyJunipersJuniperus spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulyRussian SagePerovskia spp. & cvs.low water, Central Valley1.07 gal/sq ft in JulySagebrushArtemisia spp. (shrubby)low water, Central Valley1.07 gal/sq ft in July
Minutes for your sprinklers

Turn this into minutes on your water days

Every city page has a calculator that takes smoke tree, your sprinkler type and the month, and gives the minutes per water day for that supplier's schedule. Or put it in a zone of the personal watering plan and get all twelve months printed.

Questions people ask

How often should I water smoke tree in summer?

In July, established smoke tree in loam needs a deep watering about every 20 days in the Central Valley, about every 27 days on the south coast and about every 22 days in the South Inland zone. Sandy soil holds less water, so waterings come closer together. Clay stretches them. Check the soil before each watering and skip one after a soaking rain.

How much water does smoke tree need per day?

In July in the Central Valley, established smoke tree needs about 2.7 gallons a day under a 10 foot canopy and about 11 gallons a day under a 20 foot canopy. Give it in deep waterings spread days apart rather than a little every day, so the whole root zone gets wet.

Does watering for smoke tree change across California?

Yes. WUCOLS rates smoke tree separately for each of the six California climate zones: low water in the North-Central Coastal zone, low water in the Central Valley zone, low water in the South Coastal zone, low water in the South Inland zone, low water in the High and Intermediate Desert zone, not suited to this region in the Low Desert zone. The monthly table above shows how the same rating translates into different gallon amounts as reference evapotranspiration changes.

Why is my smoke tree not producing smoke?

Hard pruning in late winter removes that year's flowers, and the plumes grow from them. Leave about a third of the old stems if you want smoke. Some cultivars are grown more for leaf color than for plumes.

Can smoke tree cause a rash?

It can. It belongs to the same family as poison ivy, and its resinous sap may irritate sensitive skin. Wear gloves and long sleeves when you prune it.

Why are my purple smoke tree leaves turning green?

Too much shade makes purple-leaved forms revert toward green. Give it full sun by moving it or thinning nearby branches. Watering changes will not restore the color.

How do I renew an overgrown smoke tree?

Cut it back in late winter to 6 to 8 inches above the ground. It regrows quickly with fresh leaves, though it skips flowering that year. Water the regrowth through its first summer.

Is smoke tree drought tolerant?

Yes, once established. Give young plants regular soakings through the first summer, then deep, occasional water. WUCOLS rates it low water in every zone except the low desert, where it is not suited.

More plant watering guides

Montezuma PineItalian Stone PinePonderosa PineTorrey PineHoney MesquiteCanyon Live OakMesa OakOregon White Oak

Sources